So I picked up 2 Cards on Sunday from a LFS (they have been there for weeks). After temp acclimating them and matching sg exactly I put them in a formalin bath for 45 mins in a 5 gallon bucket then into a 10 gallon qt. Tried to feed but they had no interest. Transferred them to other 10 gal qt when I tested ammonia level in qt tank 1 and saw it was high. Did TTM today and dosed with Prazi. Both looked great from about 130 pm til 730pm then all of a sudden the larger of the 2 does not look good. I matched salinity and temp exactly. What could I have done differently? I have been researching this for a very long time and thought I had all of my bases covered. Any help would be appreciated.